1. Field of the Invention
The present invention relates generally to methods of processing substrates and apparatuses processing substrates and particularly to such methods and apparatuses for example applying resist for example on a semiconductor wafer and removing an excess of the resist that adheres to the wafer at a peripheral edge.
2. Description of the Background Art
Generally in fabricating a semiconductor device a semiconductor wafer (hereinafter simply referred to as a “wafer”) is provided thereon with a thin film formed of indium tin oxide (ITO), an electrode pattern and the like, and to do so, photolithography is employed. In photolithography, photoresist is applied on a wafer to form a film of the resist which is in turn exposed to light in accordance with a predetermined circuit pattern which is in turn developed to form the circuit pattern in the film of the resist.
In such photolithography process when the resist is applied it is typically dropped on the wafer, which is rotated to centrifugally apply a film of the resist on a surface thereof. This resist application process results in the wafer having a side edge with an excess of the resist adhering thereto, and to remove such excess of the resist, a method is known, for example as described in Japanese Patent Laying-Open No. 2003-045788. According to this method, resist is applied on a wafer, spun away and dried, and thereafter the resist that adheres to the wafer at a peripheral edge is removed.
Another method is also known for example as disclosed in Japanese Patent Laying-Open No. 08-264412. The method provides more than once the step of causing a cleaning liquid to run round a wafer from a back surface to a front surface to remove resist or a similar applied liquid adhering to the wafer at a peripheral edge.
However, if the former method is applied, i.e., if as described in Japanese Patent Laying-Open No. 2003-045788, a wafer having resist applied thereon and dried is subsequently supplied at its back surface with a cleaning liquid to remove the resist, a long period of time may be required to remove the resist adhering to the wafer at a peripheral edge and the cleaning liquid may remain on the wafer. In particular, if the cleaning liquid is for example cyclohexanone (C6H10O) a long period of time is required to remove the resist.
Furthermore, for the latter method, i.e., as disclosed in Japanese Patent Laying-Open No. 08-264412, the cleaning liquid running round the wafer and reaching its front, peripheral edge causes the resist to scatter and again adhere to the wafer, resulting in reduced product yields.
Furthermore in order to achieve increased yields a wafer has its peripheral edge also consumed maximally to maximally obtain chips, and to do so, in recent years, the conventionally employed edge bead remover (EBR) process, i.e., a process for removing resist by approximately 3 mm as measured from the peripheral edge of the wafer, is not performed. If the EBR process is not performed, however, an arm holding the wafer may be contaminated by the resist, which may again adhere to the wafer.